6 RSA_generate_key_ex, RSA_generate_key,
7 RSA_generate_multi_prime_key - generate RSA key pair
11 #include <openssl/rsa.h>
13 EVP_PKEY *EVP_RSA_gen(unsigned int bits);
15 The following functions have been deprecated since OpenSSL 3.0, and can be
16 hidden entirely by defining B<OPENSSL_API_COMPAT> with a suitable version value,
17 see L<openssl_user_macros(7)>:
19 int RSA_generate_key_ex(RSA *rsa, int bits, BIGNUM *e, BN_GENCB *cb);
20 int RSA_generate_multi_prime_key(RSA *rsa, int bits, int primes, BIGNUM *e, BN_GENCB *cb);
22 The following function has been deprecated since OpenSSL 0.9.8, and can be
23 hidden entirely by defining B<OPENSSL_API_COMPAT> with a suitable version value,
24 see L<openssl_user_macros(7)>:
26 RSA *RSA_generate_key(int bits, unsigned long e,
27 void (*callback)(int, int, void *), void *cb_arg);
31 EVP_RSA_gen() generates a new RSA key pair with modulus size I<bits>.
33 All of the functions described below are deprecated.
34 Applications should instead use EVP_RSA_gen(), L<EVP_PKEY_Q_keygen(3)>, or
35 L<EVP_PKEY_keygen_init(3)> and L<EVP_PKEY_keygen(3)>.
37 RSA_generate_key_ex() generates a 2-prime RSA key pair and stores it in the
38 B<RSA> structure provided in I<rsa>.
40 RSA_generate_multi_prime_key() generates a multi-prime RSA key pair and stores
41 it in the B<RSA> structure provided in I<rsa>. The number of primes is given by
42 the I<primes> parameter.
43 If the automatic seeding or reseeding of the OpenSSL CSPRNG fails due to
44 external circumstances (see L<RAND(7)>), the operation will fail.
46 The modulus size will be of length I<bits>, the number of primes to form the
47 modulus will be I<primes>, and the public exponent will be I<e>. Key sizes
48 with I<num> E<lt> 1024 should be considered insecure. The exponent is an odd
49 number, typically 3, 17 or 65537.
51 In order to maintain adequate security level, the maximum number of permitted
52 I<primes> depends on modulus bit length:
54 <1024 | >=1024 | >=4096 | >=8192
55 ------+--------+--------+-------
58 A callback function may be used to provide feedback about the
59 progress of the key generation. If I<cb> is not NULL, it
60 will be called as follows using the BN_GENCB_call() function
61 described on the L<BN_generate_prime(3)> page.
63 RSA_generate_key() is similar to RSA_generate_key_ex() but
64 expects an old-style callback function; see
65 L<BN_generate_prime(3)> for information on the old-style callback.
71 While a random prime number is generated, it is called as
72 described in L<BN_generate_prime(3)>.
76 When the n-th randomly generated prime is rejected as not
77 suitable for the key, I<BN_GENCB_call(cb, 2, n)> is called.
81 When a random p has been found with p-1 relatively prime to I<e>,
82 it is called as I<BN_GENCB_call(cb, 3, 0)>.
86 The process is then repeated for prime q and other primes (if any)
87 with I<BN_GENCB_call(cb, 3, i)> where I<i> indicates the i-th prime.
91 EVP_RSA_gen() returns an I<EVP_PKEY> or NULL on failure.
93 RSA_generate_multi_prime_key() returns 1 on success or 0 on error.
94 RSA_generate_key_ex() returns 1 on success or 0 on error.
95 The error codes can be obtained by L<ERR_get_error(3)>.
97 RSA_generate_key() returns a pointer to the RSA structure or
98 NULL if the key generation fails.
102 I<BN_GENCB_call(cb, 2, x)> is used with two different meanings.
106 L<EVP_PKEY_Q_keygen(3)>
107 L<BN_generate_prime(3)>, L<ERR_get_error(3)>,
108 L<RAND_bytes(3)>, L<RAND(7)>
112 EVP_RSA_gen() was added in OpenSSL 3.0.
113 All other functions described here were deprecated in OpenSSL 3.0.
114 For replacement see L<EVP_PKEY-RSA(7)>.
118 Copyright 2000-2021 The OpenSSL Project Authors. All Rights Reserved.
120 Licensed under the Apache License 2.0 (the "License"). You may not use
121 this file except in compliance with the License. You can obtain a copy
122 in the file LICENSE in the source distribution or at
123 L<https://www.openssl.org/source/license.html>.